Did you run all of your pipe yet? I would use 1" pipe as opposed to 3/4". When you do your permanent connection to the water line in the future then you will need a back flow device like the one pictured in your link. The connections to the heads in your picture do not really allow for any height adjustment of the heads. Usually you would use a tee with a riser pipe or use flexible "swing" pipe to set the heads at the proper height.